Channel Mixer - Primaries correction

Software ART
1

Can someone explain “Channel Mixer - Primaries correction” to me a little?

You can actually see what the tool does. But there are a few things that surprise me:

To turn a face that is too red into a more pleasant orange or brown, you can set Red pirmay Hue correction to +15, for example

grafik
grafik386×113 3.28 KB

Funnily enough, you get very similar results if you set green to Hue +25 and Saturation -100.

grafik
grafik422×172 4.05 KB

Or Blue Hue -30, Saturation -20

grafik
grafik396×164 3.88 KB

All three actions reduce the magenta cast in the skin tones, but leave the other colors more or less unchanged.
Is that logical?

2

Hi,
The “primaries correction” mode does work as designed. Essentially, it allows to alter the meaning of the r, g and b components of colors as if the primaries of the working space were altered by the specified hue and saturation changes. Whether this results in unexpected behaviour largely depends on your expectations, I suppose :slight_smile:
In general, working with channel mixing is not trivial imho, and the effects are always global (but sometimes may be subtle). I doubt that you would get 100% equivalent results with different tweaks, but it’s definitely possible that they are close enough for your purposes - and for your images.

1 Like
3

Hello Alberto,
yes, the results are not really identical, the change with Green Hue makes everything more yellowish than with Red Hue, likewise with Blue Hue. But the results are surprisingly similar. I like this tool because it makes it very easy to make a red that is too cold a little warmer.